Vulcanization accelerator



Patented Aug. 29, 1933 D; ATE ,FATENTPIIZOFFICE m iiiffiii rsa.

Zaucker and Max Biigemann, Cologne- Mulheim-on-the-Rhine, Germany, assignors to kable equation:

o=$ z, 'oinaoim 1-, wherein a: means hydrogen, a substituted or unj f g j substituted allzyl-, aryl-, aralkyl-, ,alkoxyor, C N hydroaryl radical or a substituted orunsubstil 1 1' tuted amino group. I

The new accelerators may be prepared, for I N -Oi 'o example, by reacting upon accelerators contain- 1 i ing one of the group gs':- '"N#+ 35 5 90 O-sHOI \C-SH j 1 i w i According to the same method the potassium 8 salt of dimethyldithiocarbamic acidandii-nitroor a salt thereof with a nitro halogen aryl com- 4-chlorobenzoic acid methylesterreactywith. one pound containing anitro-"groupand a halogen another according to the following' bquationz- 95 v atom in orthoor para-positionto one another i i and the grouping F v 1 H (CH:):=N--C.-SK+OIC -OQOOHI 45. in meta-position to the ,nitro group. N01 1 A Y i 100 Suitable sulfhydryl compounds, are, for exs i r ample, mercapto arylene thiazoles, such as 2- l mercaptobe'nzothiazole, 2-mercapto -1'.2'-naph- )(CHZ)-N' (LS f f rm thothiazole, which compounds'may be substituted g V l 1 I, if by monovalent substituents, suclr as halogen I 105 v I. G. Farbenindustrie Aktieng es ellschafLFranlrfort on-the-Main, Germany No Drawing. Application September 16, 1932,

Serial No. 633,454,, and in Germany September is Claims.

The present invention relates to new vulcanization accelerators, to a process of vulcanizing rubber and to the vulcanization products obtainable by the said process.

It is the main object of our invention to provide vulcanization. accelerators of the above classes possessing a substantially better critical temperature. i

The accelerators which we have found to possess the desired property are those obtainable by esterifying the sulfhydryl group of compounds containing the above mentioned groupings by an aryl radical containing a nitro group and, in

meta-position to the nitro group" the group methylamino-, methoxy-, ethoxy groups' etc).

Further suitable sulfhydryl compounds are dithiocarbamates derived from'secondary amines, such as dimethylamine, diethylamine, 'methylethylamine,"dibenzylamine, ethylcyclohexylamine;

dicyclohexylarnine, N-methylaniline; piperidine,

\ 5 Compounds containing the grouping morpholine, thiomorpholine, hexahydr0carba' '60,

zoleetc.- Suitable nitro halogenaryl compounds are,for 7 7 example:-3-nitro-4 chlorobenzaldehyde, 3.3- -s. s dinitro- 4.4 -'dichlorobenzophenone, .3 -nitro-4- or h salts thereof, such a merca'ptoaf'ylene chlorobenzoic acid-methylester,2-chloror5nitrow I thiazoles or dithiocarbamates, are known to be benzoi? a i Y t -Ch10r0-5n1trovaluable vulcanization accelerators. They have, benzplpendlde q however, the disadvantage of a rather low criticaland zchlom5'mtrobenzolc acld 'butylamldetemperature I For the manufacture of the new accelerators a salt of the sulfhydryl compoundmay be caused to react'with the nitro halogen aryl compound in while gently. heating the-reaction mixture. For

example, when boiling a mixture of molecular proportions of thesodium salt of Z-mercaptobehv zothiazole: and of; 2-chloro-fi nitrobenzoic acid butylamide in acetone solution, a reactioniproduct: is obtained according to, the following prob- The new accelerators are generally "yellowish crystalline compounds soluble in-the'usual organic solvents. As outlined above,-' they; possess a good critical temperature. They, furthermore, possess a strong accelerating actiona'ndhave the advantage of not decolorizing the vulcanization products toany substantial degree.

For vulcanization purposes the new accelerators may be incorporated within the rubber to be vulcanized in any desired manner, for example, by rolling, or kneading or other mechanical means. A vulcanizing agent, such as sulfur, compounds being capable ,to split off sulfur, selenium, aromatic nitro compounds-+i-metal oxides etc. are likewise incorporated within'thevulcanization mixture, and, if desired, filling materials,.

(lamp black, zinc oxide, magnesium oxide, talcum, for example), pigments,=softeners, antiperishing agents, etc. The mixtures thus obtainable are then vulcanized in the usual manner, for

,example, by heating the same to a temperature between about 120 200 0. Hard and soft rubber vulcanization products of great technical value can thus be obtained. In some cases it will be of advantage to add to the vulcanization mixturcsrbesides the new accelerators; accelerators of other types, such as diphenylguanidine, dibutylamine, ortho-tolylbiguanidetetramethylthiuramdisulfide," 2-mercaptobenzothiazoledisulza fida t w" 1 i I K' The following examples illustrate the inventiOn, without limiting it thereto:- 7

Examplcl V: Accelerators testedr- I The-reaction products of: l r Y I; 2-mercaptobenzothiazole with 3-nitro-4- chlorobenzaldehyde II. Z-mercaptobenzothiazole with 2 chloro-5-- nitrobenzoicacid butylamide III. The sodium salt of dimethyldithiocarbamic acid with 3-'chloro-4-nitrobenzaldehyde IV. The sodium salt of dimethyldithiocarbamic acid with 3-'nitro-4-chlorobenzoic acid+methyl- 405 ester 3 1 V. The sodium salt of pentamethylene-dithiocarbamic acid with 3-nitro-4-chlorobenzoic. acid methylester v I I Accelerator I in'admixture with diphenyl- 'guanidine V VII. Accelerator III in admixture, with 2-mercaptabenzothiazole disulfide 'VIII. Accelerator IVin admixture with 2-mercaptobenzothiazoledisulfide.

No. I was tested in the mixture:

100 light crepe 5 zinc oxide l accelerator 1.5 stearic acid. No. IIwas tested in the mixture:-

100 light crepe 5 zinc oxide -3sulfur 0.5 accelerator 0. 5diphenylguanidine. I No. III, No. IVwere tested in themixture:--- 100 light crepe 5 zinc oxide 3 sulfur 1 accelerator 1 stearic acid No. V was tested in the mixture:-

100 light crepe 5 zinc oxide 2.5 sulfur laccelerator 1 stearic acid No. VI was tested in the mixture:-

100 light crepe 5 zinc oxide -2. 5 sulfur 0. 4 accelerator 0. 6 diphenylguanidine. No. VII was tested in the mixture:- Y 100 light crepe 5 :zincoxide 2.5 sulfur 5 0. .75 accelerator 0.25 2-mercaptobenzothiazoledisulfide. No. VIII was tested in the mixture:

' 100 light crepe I 5zinc oxide 2. 5 sulfur 0. 5 accelerator l 0.5 2mercaptobenzothiazoledisulfide.

(The figures given above refer to parts by weight.) In the vulcanization tests the following Values were obtained: 1 3 3 r a=tensile strength in kg/cm b stretch in I II 111 IV Heating 110 o.

a b a b a b a b A v 30 min -J 45min 88 1003 60min 31 1100 204 000 102 1120 10 min 127 1000 102 335 160 955 20 min 89 1020 133 350 152 733 231 310 45111111 161 910 220 700 127 740 171 820 v VI v11 V111 115 Heating 110 O.

a b a b a b a b 81 955 1540' III III 10 mm "100 970 130 875 102. 75s l86 5 20 min 140 825 225- 803- 149 735 202 790 45 min 170 860 220 805 740. 133' 705 7 Example 2.

Accelerators tested:- 130 mate II. The reaction pro duct'of 3 nitro-4-ch1oro benzoic acid methylester with ethylcyclohexyl- 135 dithiocarbainate. V

III. The reaction product of 3 nitro-4 -chloro benzoic acid methylesterlwith dicyclohexyl-dithiocarbamate Q I a i 1 IV. Accelerator-I inadmixture with dibenz'o thiazyl-'2.2'-disulfide' I V. Accelerator II in admixture with dibenzothiazyl -2.2',-disulfide. p 1

Nos. I and IITWBI'B tested intthe mixture:- 5

100 light crepe, 1 -5 zincoxide 3 sulfur 1 stearic acid 1. accelerator.

No. I11, IV; and V were tested in the .mixture:--

100 light'crepe a r 5 zinc oxide 3 sulfur 1 stearic acid 0. accelerator 0.25 dibenzothiazyl-2.2-disulfide. (The figures given above refer to parts by weight.) In the vulcanization tests the following values were obtained:--

a=Tensile strength in kg/cm b=Stretch in Heating, 110 C.

30 min In these examples the natural rubber applied may be replaced with a good result by artificial rubber-like masses, as are obtainable,,for example, by-polymerizing butadiene, isoprene, 2.3-dimethyl-butadiene or other rubber-forming hydrocarbbnseither alone or in admixture with one another or with other suitable polymerizable compounds, such as styrene,vinylnaphthalenes,

' acrylic acid derivatives, unsaturated ketones etc.

Therefore, when using in the claims the term rubber the same is intended to include natural rubber and artificial rubber-like masses as mentioned above. i i

1. vulcanization accelerators consisting of compounds containing one of the tautomeric groupingsr I I wherein the N02 group stands in orthoor para-position to the sulfur atom and in meta position to the carbon atom marked I, and 1 wherein a: means hydrogen, an alkyl-, ary1--,

aralkyl-, alkoxy-, hydroarylor amino group.

2. vulcanization accelerators consisting of compounds of the probable formu1a:--'

wherein the N02 group stands in orthoor paraposition to the sulfur atom and in meta-position to the carbon atom marked I, and wherein a:

means hydrogen, an alkyl-, aryl-, aralkyl-, a1koxy-, hydroarylor amino group, and wherein the nucleus marked A may be substituted by .1 monovalent substituents.

3. vulcanization. accelerators consisting compounds of the probable formulai -g r 11\ ii N O V 0= ---2 wherein the group 7 is the radical of a secondary amine, the N02 group stands in orthoor para-position to the sulfur atomand in metaposition to the carbon atom" marked I,and,.'z: stands for 'hydrogen, an alkyl-, aryl, aralkyl 'alkoxy hydroaryl-Y or amino group.

- 4. The vulcanization accelerator of'the prob H able formulaze I CO.NH.(CH 2)a.CHa

6. The vulcanization accelerator of the prob able 7 formula I NO: 8 0H. s 0

NCS -o 1 CH: V H

7. The process which comprises incorporating l q 5. Thevulcanization accelerator of the probable forniulaz- 1,

within rubber a vulcanizing agent and a vulcanization accelerator containing one of the tautomeric groupings: r

C-S-aryl-NO: and GS-aryl-NO,

, S' 0 -a: S 0:0-2:

I l I wherein the NO: group stands in orthoor paraposition to thesulfur atom and in meta-position to the carbon atom marked I, and wherein a: means hydrogen; an alkyl-, aryl-, aralkyl-, alkoxy-, hydroaryl or amino group, and vulcanizing the mixture.

8. The process which comprises incorporating within rubber sulfur and a compound of the probable formula wherein the Nb: group stands in orthoor paraposition to the sulfur atom and inmeta-position to the carbon atom marked I, wherein a: means hydrogen, an alkyl-, aryl- ,ara1ky1, alkoxy-, hy-

droarylor amino group,-and vwherein the nucleus marked I may be substituted-by monovalent substituent's, and vulcanizing the mixture.

9. The process which comprises incorporating 'Within'rubbersulfur and a compound of theprobable formula:-

and vulcanizing the mixture. 7

11. The process which comprises incorporating 12. The processwhich comprises incorporating within rubber sulfur p and a compound of probable formula:

- 0113]."; H v and vulcanizing the mixture. 7

13. The vulcanization products obtained cording to the process claimed in claim 7.

14. The vulcanization products obtained."

cording to the process claimed in claim 8.

'l5.- The vulcanization products obtained cording to the process claimed in claim 9.

16. The vulcanization products obtained cording to the process claimed in claim 10.

1'7. The vulcanization products obtained cording to the process claimed in claim 11.

18. The vulcanization products obtained cording to the process claimed in claim '12.

the

LUDWIG ORTHNER.

EwALD ZAUCKER. I I MAX BOGEMANN.

within rubber sulfur and a compound of the probable formula 7 i N02 0113 S NC-S 002.0113 v CH3 and vulcanizing the mixture. 

